- The presence of immunoglobulin E (IgE)-mediated hypersensitivity to dust mite, cockroach, mold, cat or dog dander, confirmed by a positive response to skin prick testing at the Visit 1. A positive response is defined as a wheal diameter of ≥5 mm larger than the negative control for the skin prick test. Histamine control must also be positive with a wheal diameter >5 mm larger than the control. If there are prevailing seasonal allergies, the subject must have a negative skin test to the specific allergen.